Good Afternoon, Ben,
I can't offer much specific advice on cleaning or restoration, except to go extremely slowly and carefully, preferably starting on an unimportant print and in a peripheral area of the print. Kodak Film Cleaner might work, depending on the type of foreign material on the print. Best advice in such situations is to make a high-quality copy negative of each print FIRST, before any cleaning or restoration is attempted. It's getting harder to find specialized copy films nowadays, but something like Kodak Commercial (4127) or Kodak Professional Copy (4125) sheet films would be ideal for copying old B & W prints.